Polyvinyl chloride resin compositions stabilized for use in food packaging



United States 3,004,000 POLYVINYL CHLORIDE RESIN CQMPOSITIONS STABILIZED FOR USE IN FOOD PACKAGING Otto S. Kauder, Jamaica, and Norman L. Perry, Seaford,

N.Y., assignors to Argus Chemical Corporation, a corporation of New York a No Drawing. Filed'Mar. 15, 1960, Ser. No. 15,060 20 Claims. (Cl. 260-4515) atent '5 ganotin compounds. Among these patents are Nos.

2,883,363, issued April 21, 1959; 2,872,468, issued February 3, 1959; 2,870,182 and 2,870,119, issued Ja u nary 20, 1959; all to Leistner and Hecker, No. 2,914,506, issued November 24, 1959, to Mack and Parker, and 2,801,258, issued July 30, 1957, to Johnson. Organotin compounds because of their unusual heat stabilizing properties have now set a standard for heat stability which remains unequaled. However, the organotin compounds have the disadvantage that they are toxic, and this limits their use to applications where toxicity is not a problem. Moreover, most of these compounds are liquids, and therefore of limited utility with rigid vinyl polymers.

In accordance with the instant invention, polyvinyl chloride resins which are safe for use in food packaging and which have remarkable heat stability at elevated temperatures are obtained using as the stabilizer system a calcium-zinc salt combination composed of a member of the group consisting of calcium and Zinc benzoates, a member of the group consisting of calcium and zinc salts of the mixed fatty acids derived from edible fats and oils, and sorbitol. Mixtures of the calcium and zinc benzoates and calcium and zinc salts can be used. The stability to long term heating imparted by this combination is extremely good, equaling or bettering that furnished, for example, by alkyl tin mercaptides. Because the stabilizer combination is a solid, this stabilization is obtainable without deterioration of any of the other properties of the resin. The compositions of the invention are stable at the extraordinarily high temperatures which are required in the case of rigid polymers, as compared to plasticized polyvinyl chloride resins, i.e., at temperatures of 375 F. and higher. They also are safe to use in food packaging, which makes it possible to use the rigid nonplasticized polyvinyl chloride resin compositions of the invention in the fabrication of food containers. r

The stabilizer-system of the invention is far more effective than any of the ingredients thereof taken alone or in pairs showing that the combination of all three components, i.e., the calcium and zinc benzoate and salts of the mixed fatty acids derived from edible fats and oils, and sorbitol, gives a synergistic effect. Combinations, for example, of calcium benzoate and sorbitol, of zinc salts and sorbitol, and of calcium benzoate and zinc salts, are not sut ficiently effective at the elevated processing temperatures, i.e., 375? F. and higher, required in the processing of rigid polymers to be useful stabilizers. Combinations of zinc stearate or calcium stearate and sorbitol are disclosed in Patent No. 2,711,401 to Robert E. Lally, patented June 21, 1955. a

The proportions of the three components of the stabilizer system of the invention are quite critical in obtaining effective stabilization under the required conditions. Good'stabilization is obtained at proportions within the range from about 15 to about 40 parts of the benzoate, from about 15 to about 50 parts of the fatty acid salts, and from about 20 to about 60 parts of sorbitol. Preferably, the stabilizer system contains 3 parts of thebenzoate, 3 parts of the fattyacid salts, and 3 parts of sorbitol. It will be understood that the term fatty acid salts refers to the calcium and zinc salts of the mixed fatty acids derived from edible fats and oils. Exemplary are the mixed fatty acids derived from tallow, coconut oil,

oils from which the fatty acids are derived may be 5 hydrogenated, if desired. Also useful are the distilled fractionated fatty acid mixtures derived from such oils.

The amount of the stabilizer system should be sufficient to permit heating of the stabilized polyvinyl chloride resin composition at 375 for at least one hour without the development of heat decomposition. Usually, from 3 to 6% stabilizer system by weight of the resin will be sufficient to meet most needs in use. Good resistance to heat deterioration is obtainable employing only small amounts of the stabilizer system, as little as 1% by Weight of the resin. The more stabilizer employed, the better the resistance to heat deterioration, up to amounts of 6% by weight of the resin. Beyond this, the stabilization effect may not be greatly enhanced, and such larger amounts may accordingly be wasteful. However, amounts up to 10% can be employed if desired.

The invention is applicable to any polyvinyl chloride resin. .The term polyvinyl chloride as used herein is inclusive not only of polyvinyl chloride homopolymers but. also of copolyme rs' of vinyl chloride in a major proportion and other copolymerizable monomers in' a minor proportion, such as copolymers of vinyl chloride and vinyl acetate, copolymers of vinyl chloride with maleic or fumaric acid, and copolymers of vinyl chloride with styrene. The invention also is applicable to tures of polyvinyl chloride in a major proportion with a minor proportion of other synthetic resins such' as chlorinated polyethylene or a copolymer of acrylonitrile, butadiene and styrene. V

The invention is of particular application to the stabilization'of rigid polyvinyl chloride resin compositions, that is, resin compositions which are formulated to. with-. stand high temperatures, ofthe order 0f 3 F. and higher. Plasticization of such polymersispermissible provided this does not reduce the softening point of the resin. to below the temperature to which it must be subjected. However, the stabilizer systems of the invention can be used with platicized polyvinyl chloride resin compositions of conventional formulation where high softena ing point is not a requisite. Conventional plasticizers well known to those skilled in the art can be employed such-as, for example, dioctyl'phthalate and octyl d i-* system with the resin on a two roll mill at from 300 to 400 F. 'for a time'suflicient to form a homogeneous sheet. a The plasticizer, if one is employed, is incorporated with the stabilizer. Usually, fiveminutes milling time is adequate. After the mass is uniform, it is sheeted a r the usual way.

Patented Oct; 10, 19 61 1 The following examples in the opinion of the inventors constitute the preferred embodiments of their invention:

resin. The composition was then held in an oven at 375 F. to determine its heat stability. The color noted was as reported in Table II below.

Table II InitialLight Yellow After minutes of heating-Yellow After minutes of heating-Yellow After 45 minutes of heatingYellow After 60 minutes of heatingYellow After 75 minutes of heating-Yellow with dark edges After 90 minutes of heating-Black In these proportions the stabilizer system does not impart quite as good heat resistance when used in the same Table I Parts Heat discoloration for minutes of heating per 150 7 parts of resin Initial 15 30 45 60 75 90 105 120 Control-no stabilizer-. White Darkbrown. Black. Black- Blaek Black". Black Black Black. I--. Calcium benzoate 9 Medium do do do do do do do. Do.

rown. IL--- Zine salts of tallow 9 White---" Black Black do d0 d0 do. do.. Do.

fatty acids. III. Sorbitol 9 do Dark grey d0 do do. do do.-- do. Do.

Calcium benzoate 4. 5 IV Zinc salts of tallow 4.5 do"..- Black do do do .do do do Do.

cii ii t 4 5 D k d clnm enzoa e ar re 1 t fi i2 d Red Darkred $1 1 brown. do... do .do do.. D0. Zinc 52 s 0 ta OW Bri ht Bri ht e ow- VI- fatty acids. Oream g g black do do do. do Do.

{Sorbitol 4.5 yellow yellow edges.

li ll P l L ht inc sa s o a ow ae lg v11..- fatty acids yellow }Yellow Yellow Yellow Yell0w Yellow Yellow Yellow.. brown Sorbitol 1:1:l 3. 0

It is apparent from the above results that the stabilizer amount as Sample VII of Table I. However, better stasystcm of the invention in the proportions indicated in VII gave by far the best results. The calcium benzoate, zinc salts of mixed tallow fatty acids and sorbitol alone, I, II and HI, respectively, were completely inefiective, being no better than the control. The combinations of two of these, calcium benzoate and zinc salts of mixed tallow fatty acids, calcium benzoate and sorbitol, and the zinc salts of tallow fatty acids and sorbitol, Samples IV, V and VI, respectively, gave a slight improvement in heat resistance, but not enough to be acceptable. The difference between these and VII is very striking.

The stabilizer system of the invention retains clarity and good initial color in the stabilized resin formulation. The very high heat resistance at 375 F. is, of course, a measure of the heat resistance at ordinary atmospheric temperatures and shows that the compositions of the invention have a useful life under such conditions of at least three times that of the other compositions tested. This is a remarkable improvement.

Tests showed Sample VII to be nontoxic.

It is apparent from the above results that the stabilizer system of the invention gave a distinct improvement in preventing initial discoloration, and also discoloration after 120 minutes of heating. The other stabilizer combinations did not give nearly as good stability; in some cases the stabilization ended after about 30 minutes of heating, and in the remaining cases, heat decomposition set in after about 60 minutes of heating.

EXAMPLE 2 v A series of compositions was made up as in Example 1 employing a copolymer of 96% vinyl chloride and 4% vinyl acetate. Similar results were obtained.

EXAMPLE 3 A stabilizer system was prepared composed of calcium benzoate 3.6 parts, zinc salts of mixed tallow fatty acids 3.6 parts, and sorbitol 1.8 parts. This stabilizer system was used in accordance with Example 1 in the amount of 9 parts by weight with 150 parts by weight of- Geon 103 Ep bilization could be obtained by using more of the stabilizer system by weight of the resin.

EXAMPLE 4 A stabilizer system was prepared composed of a mixture of the calcium benzoate 2.25 parts, zinc salts of mixed tallow fatty acids 2.25 parts, and sorbitol 4.5 parts. This stabilizer system was used in accordance with Example 1 in the amount of 9 parts by weight with 150 parts by weight of Geon 103 Ep resin. The composition was then held in an oven at 375 F. to determine its heat stability. The color noted was as reported in Table HI below.

Table III Initial-Pale Yellow After 15 minutes of heatingYellow After 30 minutes of heating-Yellow After 45 minutes of heating-Yellow After 60 minutes of heatingYellow After 75 minutes of heating-Yellow After minutes of heating-Yellow After 105 minutes of heating-Yellow After minutes of heating-Brown This stabilizer system is practically as good as Sample VII of Table I, giving stabilization up to 105 minutes at 375 F. instead of up to 120 minutes.

EXAMPLE 5 The series of formulations of Example 1 were prepared again, substituting zinc salts of the mixed fatty acids derived from coconut oil for the tallow fatty acids used in that example. The same results were obtained. The composition corresponding to Sample VII imparted adequate heat resistance for 120 minutes of heating at 375 F., whereas the other compositions tested gave stabilization only for about 45 minutes of heating.

EXAMPLE 6 The series of formulations of Example 1 were prepared.

again, substituting zinc salts of the mixed fatty acids derived from hydrogenated cottonseed oil for the tallow fatty acids used in that example. The same results were obtained. The composition corresponding to Sample VII imparted adequate heat resistance for 120 minutes of heating at 375 F., whereas the other compositions tested being no better than the control; The combinations of two. of these, zinc benzoate and calcium salts of mixed tallow fatty acids, zinc benzoate and sorbitol, and the calcium salts of tallow 'fatty acids, andsorbitoL Samples gave stabilization only for about 45 minutes of heating. XI, Xi-I and XIII, respectively, gave a slight improvement inheat resistance, but not enough to be acceptable. The EXAMPLE 7 diiference between these and XIV is very striking.

The sefies of formulations of Example 1 Were P p The stabilizer system of the invention retains clarity and again, substituting Zine Salts of the mixed fatty acids good initial color in the stabilized resin formulation. The rived from hydrogenated COID Oil. for the tallow fatty acids 10 very heat resistance at 375 is of gourse a megsused in that example. The same results were obtained. u e of the heat resistance at ordinary af nosphe -ic tam- The composition Corresponding to Sample VII imparted peratures and shows that the compositions of the invention adequate heat Iesistelllee 120 minutes of heating at have a useful life under such conditions of at least three Whereas the other compositions tested gave times that of the other compositions tested. This is a bilization only fOI about 45 minutes Of heating. remarkable improvement EXAMPLE 8 Tests showed Sample XIV to be nontoxic. It is apparent from the above results that the stabilizer T sane? offiomhllatms of EXamPle 1 were PI'FPaIed system of the invention gave a distinct improvement in 35am, substltutmg. 9 salts of the med fatty aclds preventing initial discoloration, and also discoloration nved from mamt 011 for the tallow fatty acids used m after 120 minutes of heating. The other stabilizer comthat PP The m results were h The binations did not give nearly as good stability; in some composition corresponding to Sample VII impart cases the stabilization ended after about 30 minutes of quate heat resistance for 120 minutes of heating at 375 heating, and in the remaining cases, heat decomposition F., whereas the other compositions tested gave stabilizaset in after about 60 minutes of heating tiononly for about 45 minutes of heatmg. 25 E PLE 11 EXAMPLE 9 I A series of compositions was made up as in Example A composltlon was Pf exactly P EmmP1e 1 10 employing a copolymer of 96% vinyl chloride and 4% employmg as the stablhzer system a mum: of 3 Parts vinyl acetate. Similar results were obtained. calcium benzoate, 3 parts of zinc salts of tallow fatty acids, and 3 parts pentaerythritol. This stabilizer system EXAMPLE 12 was used in the amount of 9 Parts y Weight With 150 A stabilizer system was prepared composed of zinc Parts y Weight of Geeh 103 P resilil- The Stabilization benzoate 1.5 parts, calcium salts of mixed tallow fatty obtaine en the resin composition was held in all even acids 3 parts, and sorbitol 3 parts. This stabilizer system at 375 was equivalent t0 that Of Sample VHOf Table was used in accordance with Example 10 in the amount Thus, pentaerythritol is an equivalent of sorbitol, but it of 7.5 parts by Weight with 150 parts by Weight of Geon ld t be p y in the stabilizer ys s of t 103 Ep resin. The composition was then held in an oven invention at the Present time, because pontaerythritol i at 375 F. todetermine its heat stability. The color not accepted as safe to use in feed Packaging noted was as reported in Table V below.

EXAMPLE 10 Table V Plastic composition: Parts by weight 1111. ti a1 Pale Yellow ig (homopolymer of polyvmyl 150 After 15 minutes of heating-Yellow a After 30 minutes of heatingYellow Stabilizer system as noted m Table IV After 45 minutes of heatingYelloW The stabilizers were blended with the polyvinyl chloride After minutes of heating-Yellow on a two roll mill up to 375 F. and then held in an oven After minutesof heating--Ye1low at 375 F. to determine their heat stability. The dis- After minutes of heating-Yellow coloration was noted and is reported in Table IV below. After minutes of heating-Black Table IV Parts 7 Heat discoloration for minutes of heating per 150 parts ofresin Initial 15 30 4s 60] 75 90 105 C0ntr0lnostabi1izer White- Darkbrownl Black Black Black--- Black.-- Black.-- Blaek 'Black VIII Zincbenzoate 9 (f) 1 1 IX Calcium salts oftailow 9 Medium Darkbrown. Darkbrown. Darkbrowm Dark Black- Black--- Black.-. Black fatty acids. brown. Brown X sorbitol; 9' White.-. Darkgrey..- Black Black Black". do.--- do .do Do. Zinc benzoate 4. 5 I XI {Calcium salts or tallow 4.5 .do..-. Black do; .-d0 do. do do do- Do.

fatty Mottled Mottled I rfi ifififffiiiiiiiii 2:? Yellow 1: l aa Zinebenzoate 3.0 XIV ;g g; oz tallow }Grearn Pale yellow- Pale yellow- Pale yellow. Yell0w. Yell0w Yellow Yel1ow. Yellow.-

Sorbitollzlzl 3.0

1 Decomposed on the mill.

It is apparent from the above results that the stabilizer system of the invention in the proportions indicated in XIV gave by far the best results. The zinc benzoate, calcium salts of mixed tallow fatty acids and sorbitol alone,

In these proportions the stabilizer system does not imthe same amount of Sample X[V of Table IV, Better sta- VHI, IX and X, respectively, were completely ineflEective, 75 system by Weight of the resin.

bilization could be obtained by using more of the stabilizer 7 EXAMPLE 13 A stabilizer system was prepared composed of a mixture of the zinc benzoate 2 parts, calcium salts of mixed tallow fatty acids 3 parts, and sorbitol 3- parts. This stabilizer system was used in accordance with Example in the amount of 8 parts by weight with 150 parts by weight of Geon 103 Ep resin. The composition was then held in an oven at 375 F. to determine its heat stability. The color noted was as reported in Table VI below.

Table VI Initials-Pale Yellow After minutes of heating-Yellow After 30 minutes of heating-Yellow After 45 minutesof heating-Yellow After 60 minutes of heatingYel1ow After 75 minutes of heating-Yellow After 90 minutes of heating-Yellow After 105 minutes of heating-Yellow After 120 minutes of heating-Black This stabilizer system gave stabilization up to 105 min utesat 375 F. instead of up to 120' minutes, but only 8 parts was used as compared to 9 parts in Sample XIV in Table IV.

EXAMPLE 14 A stabilizer system was prepared composed of zinc benzoate 2.25 parts calcium salts of mixed tallow fatty acids 2.25 parts, and sorbitol 4.5 parts. This stabilizer system was used in accordance with Example 1 in the amount of 9 parts by weight with 150 parts by weight of Geon 103 Ep resin. The composition was then held in an oven at 375 F. to determine its heat stability. The color noted was as reported in Table VII below.

Table VII Initial-Pale Yellow After 15 minutes of heating-Pale Yellow After 30 minutes of heating-Pale Yellow After 45 minutes of heating-Yellow After 60 minutes of heating-Yellow After 75 minutes of heating-Yellow After 90 minutes of heatingYellow After 105 minutes of heating-Yellow After 120 minutes of heatingYellow In these proportions the stabilizer system imparts quite as good heat resistance as Sample XIV of Table IV.

EXAMPLE. 15

The series of formulations of Example 10 were prepared again, substituting calcium salts of the mixed fatty acids derived from coconut oil for the tallow fatty acids used in that example. The same results were obtained. The composition corresponding to Sample XIV imparted adequate heat resistance for 120- minutes of heating at 375 F., whereas the other compositions tested gave stabilization only for about 45 minutes of heating.

EXAMPLE 16 The series of formulations of Example 10 were prepared again, substituting calcium salts of the mixed fatty acids derived from hydrogenated cottonseed oil for the tallow fatty acids used in that example. The same results were obtained. The composition corresponding to Sample XIV imparted adequate heat resistance for 120 minutes of heating at 375 F., Whereas the other compositions tested gav'e stabilization only for about 45 minutes of heating.

EXAMPLE 17 The series of formulations of Example 10 were prepared again, substituting calcium salts of the mixed fatty acids derived from hydrogenated corn oil for the tallow fatty acids used in that example. The same results were obtained. The composition corresponding to Sample acids, and 3 parts pentaerythritol.

XIV imparted adequate heat resistance for minutes of heating at 375 F., whereas the other compositions tested gave stabilization only for about 45 minutes of heating.

EXAMPLE 18 EXAMPLE 19 A composition was prepared exactly as in Example 10 employing as the stabilizer system a mixture of 3 parts zinc benzoate, 3 parts of calcium salts of tallow fatty This stabilizer system was used in the amount of 9 parts by weight with parts by weight of Geon 103 Ep resin. The stabilization obtained when the resin composition was held in an oven at 375 F. was equivalent to that of Sample XIV of Table IV. Thus, pentaerythritol is an equivalent of sorbitol, but it would not be employed in the stabilizer systems of the invention at the present time, because pentaerythritol is not. accepted as safe to use in food packaging. I

We claim:

1. A polyvinyl chloride resin stabilizer composition capable of improving the resistance of the resin to heat deterioration when heated at 375 F. consisting essentially of a mixture of calcium and zinc salts of which at least one is selected from the group consisting of zinc benzoate and calcium benzoate, and at least one of the other salts is selected from the group consisting of the calcium salts of mixed fatty acids derived from edible fats and oils, and the zinc salts of mixed fatty acids derived from edible fats and oils, and sorbitol, in the proportions of from about 15 to about 40 parts of the benzoate, from about 15 to about 50 parts of the fatty acid salts, and from 20 to about 60 parts of sorbitol.

2. A polyvinyl chloride resin stabilizer composition in accordance with claim 1 inwhich the benzoate, fa'tty 'acid salts and sorbitol are in the proportion of 1:1:1.

3. A polyvinyl chloride resin stabilizer composition in accordance with claim 1 in which the fatty acids are tallow fatty acids.

4. A polyvinyl chloride resin stabilizer composition in accordance with claim 1 in which the fatty acids are co conut oil fatty acids.

5. A polyvinyl chloride resin stabilizer composition in accordance with claim 1 in which the fatty acids are hydrogenated cottonseed oil fatty acids.

6. A polyvinyl chloride resin stabilizer composition in accordance with claim 1 in which the fatty acids are hydrogenated corn oil fatty acids.

7. A polyvinyl chloride resin stabilizer composition in accordance with claim 1 in which the fatty acids are peanut oil fatty acids.

8. A polyvinyl chloride resin composition having improved resistance to heat deterioration consisting essen-' tiall of a polyvinyl chloride resin, and a stabilizer comand zinc salts of which at least one is selected from the group consisting of zinc benzoate and calcium benzoate, and at least one of the other salts is selected from the group consisting of the calcium salts of mixed fatty acids derived from edible fats and oils, and the zinc salts of mixed fatty acids derived from edible fats and oils, and sorbitol, in the proportions of from about 15 to about 40 parts of the benzoate, from about 15 to about 50 parts of the fatty acid salts, and from about 20 to about 60 parts of sorbitol, the said stabilizer composition being present in an amount to improve the resistance to 9 heat deterioration when the composition is heated at 375 F.

9. A polyvinyl chloride resin composition in accordance with claim 8 in which the polyvinyl chloride resin is a polyvinyl chloride homopolymer.

10. A polyvinyl chloride resin composition in accordance with claim 8 in which the polyvinyl chloride resin is a copolymer of vinyl chloride and vinyl acetate.

11. A polyvinyl chloride resin composition in accordance with claim 8 in which the benzoate, fatty acid salts and sorbitol are in the proportion of 1:1:1.

12. A polyvinyl chloride resin composition in accordance with claim 8 in which the fatty acids are tallow fatty acids.

13. A polyvinyl chloride resin composition in accordance with claim 8 in which the fatty acids are coconut oil fatty acids.

14. A polyvinyl chloride resin composition in accordance with claim 8 in which the fatty acids are hydrogenated cottonseed oil fatty acids.

15. A polyvinyl chloride resin composition in accordance with claim 8 in which the fatty acids are hydrogenated corn oil fatty acids.

16. A polyvinyl chloride resin composition in accordance with claim 8 in which the fatty acids are peanut oil fatty acids.

17. A polyvinyl chloride resinstabilizer composition capable of improving the resistance of the resin to' heat deterioration when heated at 375 F. consisting essentially of calcium benzoate, the zince salts of mixed fatty acids derived from edible fats and oils, and sorbitol, in the proportions of from about to about 40 parts of the calcium benzoate, from about 15 to about 50 parts of the zinc salts, and from about to about 60 parts of sorbitol. V

18. A polyvinyl chloride resin stabilizer composition capable of improving the resistance of the resin to heat deterioration when heated at 375 F. consisting essentially of zinc benzoate, the calcium salts of mixed fatty acids derived from edible fats and oils, and sorbitol, in the proportions of from about 15 to about parts of the zinc benzoate, from about 15 to about parts of the,

calcium salts, and from about 20 to about parts of sorbitol.

19. A polyvinyl chloride resin composition having improved resistance to heat deterioration consisting essentially of a polyvinyl chloride resin, and a stabilizer composition consisting essentially of calcium benzoate, the zinc salts of mixed fatty acids derived from edible fats and oils, and sorbitol, in the proportions of from about 15 to about 40 parts of the calcium benzoate, from about 15 to about 50 parts of the zinc salts, and from about 20 to about 60 parts of sorbitol, the said stabilizer composition being present in an amount to improve the resistance to heat deterioration when the composition is heated at 375 'F.

20. A polyvinyl chloride resin composition having improved resistance to heat deterioration consisting essentially of a polyvinyl chloride resin, and a stabilizer composition consisting essentially of zinc benzoate, the calcium salts of mixed fatty acids derived from edible fats and oils, and sorbitol, in the proportions of from about 15 to about 40 parts of zinc benzoate, from about 15 to about 50 parts of the calcium salts, and from about 20 to about 60 parts of sorbitol, the said stabilizer composion being present in an amount to improve the resistance to heat deterioration when the composition is heated at 375 F.

References Cited in the file of this patent UNITED STATES PATENTS 2,711,401 Lally June 21, 1955 2,918,451 Elliott Dec. 22, 1959 2,935,491 Mack May 4, 1960 UNITED STATES PATENT. OFFICE GERTIFICATE OF COREGTIGN Patent No, 3' OO4 OOO Gotober 10 1961 Qtto Sc Keauder et e1a It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below, v

Columns 3 and 4 Table I column 6 line 2 thereoi for "do" read Dark brown columns 5 and 61 Table IV column. 2 line 15 therecf for Clacium read Calcium column 9 line 3O for "'zince read zine column 10 line 37,,

for May 4 1960" read May 3 1960 e Signed and sealed this 20th day of March 1962,

(SEAL) Attest: I DAVID L. LADD ERNESTWO SWIDER h e Attesting Officer Commlssloner i" UNITED STATES PATENT. OFFICE CERTIFICATE OF CORRECTIDN Patent No 3OOQ OOO Uctober l0 l96l ()tto Sn Kauder et ela It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below a t Golumns 3- and 4 Table I column o line 2 thereof for "'do read Dark brown columns 5 and 6 Teble TV column 2} line 15 thereof 9 for Claolumra read Calcium ooluamn 9 line 3O for 'zinee read zine column 10, line 37 for May 4; 1960" read May 3 l960 "0 Signed and sealed this 20th day of March l962 (SEAL) it: Attes DAVID L. LADD ERNEST D Commissioner of Patents Attestlng Officer 

1. A POLYVINYL CHLORIDE RESIN STABILIZER COMPOSITION CAPABLE OF IMPROVING THE RESISTNCE OF THE RESIN TO HEAT DETERIORATION WHEN HEATED AT 375*F. CONSISTING ESSENTIALLY OF A MIXTURE OF CALCIUM AND ZINC SALTS OF WHICH AT LEAST ONE IS SELECTED FROM THE GROUP CONSISTING OF ZINC BENZOATE AND CALCIUM BENZOATE, AND AT LEAST ONE OF THE OTHER SALTS IS SELECTED FROM THE GROUP CONSISTING OF THE CALCIUM SALTS OF MIXED FATTY ACIDS DERIVED FROM EDIBLE FATS AND OILS, AND THE ZINC SALTS OF MIXED FATTY ACIDS DERIVED FROM EDIBLE FATS AND OILS, AND SORBITOL, IN THE PROPORTIONS OF FROM ABOUT 15 TO ABOUT 40 PARTS OF THE BENZOATES, FROM ABOUT 15 TO ABOUT 50 PARTS OF THE FATTY ACID SALTS, AND FROM 20 TO ABOUT 60 PARTS OF SORBITOL. 